X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/17e22c50bfd623e2b3b393dbcb838e82c76f2e69..44bcee116e0c56abe8027afcb1a3575fdc6ff732:/include/wx/scopeguard.h diff --git a/include/wx/scopeguard.h b/include/wx/scopeguard.h index 8d5795f13f..45fe82f5bf 100644 --- a/include/wx/scopeguard.h +++ b/include/wx/scopeguard.h @@ -11,8 +11,9 @@ /* Acknowledgements: this header is heavily based on (well, almost the exact - copy of) wxScopeGuard.h by Andrei Alexandrescu and Petru Marginean published + copy of) ScopeGuard.h by Andrei Alexandrescu and Petru Marginean published in December 2000 issue of C/C++ Users Journal. + http://www.cuj.com/documents/cujcexp1812alexandr/ */ #ifndef _WX_SCOPEGUARD_H_ @@ -26,8 +27,41 @@ // helpers // ---------------------------------------------------------------------------- +#ifdef __WATCOMC__ + +// WATCOM-FIXME: C++ of Open Watcom 1.3 doesn't like OnScopeExit() created +// through template so it must be workarounded with dedicated inlined macro. +// For compatibility with Watcom compilers wxPrivate::OnScopeExit must be +// replaced with wxPrivateOnScopeExit but in user code (for everyone who +// doesn't care about OW compatibility) wxPrivate::OnScopeExit still works. + +#define wxPrivateOnScopeExit(guard) \ + { \ + if ( !(guard).WasDismissed() ) \ + { \ + wxTRY \ + { \ + (guard).Execute(); \ + } \ + wxCATCH_ALL(;) \ + } \ + } + +#define wxPrivateUse(n) wxUnusedVar(n) + +#else + +// namespace support was first implemented in gcc-2.95, +// so avoid using it for older versions. +#if !defined(__GNUC__) || wxCHECK_GCC_VERSION(2, 95) + +#define wxHAS_NAMESPACES + namespace wxPrivate { +#else +#define wxPrivate +#endif // in the original implementation this was a member template function of // ScopeGuardImplBase but gcc 2.8 which is still used for OS/2 doesn't // support member templates and so we must make it global @@ -50,7 +84,14 @@ namespace wxPrivate void Use(const T& WXUNUSED(t)) { } +#if !defined(__GNUC__) || wxCHECK_GCC_VERSION(2, 95) } // namespace wxPrivate +#endif + +#define wxPrivateOnScopeExit(n) wxPrivate::OnScopeExit(n) +#define wxPrivateUse(n) wxPrivate::Use(n) + +#endif // ============================================================================ // wxScopeGuard for functions and functors @@ -65,6 +106,12 @@ class wxScopeGuardImplBase public: wxScopeGuardImplBase() : m_wasDismissed(false) { } + wxScopeGuardImplBase(const wxScopeGuardImplBase& other) + : m_wasDismissed(other.m_wasDismissed) + { + other.Dismiss(); + } + void Dismiss() const { m_wasDismissed = true; } // for OnScopeExit() only (we can't make it friend, unfortunately)! @@ -73,12 +120,6 @@ public: protected: ~wxScopeGuardImplBase() { } - wxScopeGuardImplBase(const wxScopeGuardImplBase& other) - : m_wasDismissed(other.m_wasDismissed) - { - other.Dismiss(); - } - // must be mutable for copy ctor to work mutable bool m_wasDismissed; @@ -86,6 +127,9 @@ private: wxScopeGuardImplBase& operator=(const wxScopeGuardImplBase&); }; +// wxScopeGuard is just a reference, see the explanation in CUJ article +typedef const wxScopeGuardImplBase& wxScopeGuard; + // ---------------------------------------------------------------------------- // wxScopeGuardImpl0: scope guard for actions without parameters // ---------------------------------------------------------------------------- @@ -99,7 +143,7 @@ public: return wxScopeGuardImpl0(fun); } - ~wxScopeGuardImpl0() { wxPrivate::OnScopeExit(*this); } + ~wxScopeGuardImpl0() { wxPrivateOnScopeExit(*this); } void Execute() { m_fun(); } @@ -130,7 +174,7 @@ public: return wxScopeGuardImpl1(fun, p1); } - ~wxScopeGuardImpl1() { wxPrivate::OnScopeExit(*this); } + ~wxScopeGuardImpl1() { wxPrivateOnScopeExit(* this); } void Execute() { m_fun(m_p1); } @@ -162,7 +206,7 @@ public: return wxScopeGuardImpl2(fun, p1, p2); } - ~wxScopeGuardImpl2() { wxPrivate::OnScopeExit(*this); } + ~wxScopeGuardImpl2() { wxPrivateOnScopeExit(*this); } void Execute() { m_fun(m_p1, m_p2); } @@ -200,7 +244,7 @@ public: return wxObjScopeGuardImpl0(obj, memFun); } - ~wxObjScopeGuardImpl0() { wxPrivate::OnScopeExit(*this); } + ~wxObjScopeGuardImpl0() { wxPrivateOnScopeExit(*this); } void Execute() { (m_obj.*m_memfun)(); } @@ -228,7 +272,7 @@ public: return wxObjScopeGuardImpl1(obj, memFun, p1); } - ~wxObjScopeGuardImpl1() { wxPrivate::OnScopeExit(*this); } + ~wxObjScopeGuardImpl1() { wxPrivateOnScopeExit(*this); } void Execute() { (m_obj.*m_memfun)(m_p1); } @@ -258,7 +302,7 @@ public: return wxObjScopeGuardImpl2(obj, memFun, p1, p2); } - ~wxObjScopeGuardImpl2() { wxPrivate::OnScopeExit(*this); } + ~wxObjScopeGuardImpl2() { wxPrivateOnScopeExit(*this); } void Execute() { (m_obj.*m_memfun)(m_p1, m_p2); } @@ -280,56 +324,161 @@ wxMakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2) MakeObjGuard(obj, memFun, p1, p2); } +// ---------------------------------------------------------------------------- +// wxVariableSetter: use the same technique as for wxScopeGuard to allow +// setting a variable to some value on block exit +// ---------------------------------------------------------------------------- + +#ifdef wxHAS_NAMESPACES + +namespace wxPrivate +{ + +// empty class just to be able to define a reference to it +class VariableSetterBase { }; + +typedef const VariableSetterBase& VariableSetter; + +template +class VariableSetterImpl : public VariableSetterBase +{ +public: + VariableSetterImpl(T& var, const U& value) + : m_var(var), + m_value(value) + { + } + + ~VariableSetterImpl() + { + m_var = m_value; + } + +private: + T& m_var; + const U& m_value; + + // suppress the warning about assignment operator not being generated + VariableSetterImpl& operator=(const VariableSetterImpl&); +}; + +template +class VariableNullerImpl : public VariableSetterBase +{ +public: + VariableNullerImpl(T& var) + : m_var(var) + { + } + + ~VariableNullerImpl() + { + m_var = NULL; + } + +private: + T& m_var; + + VariableNullerImpl& operator=(const VariableNullerImpl&); +}; + +} // namespace wxPrivate + +template +inline +wxPrivate::VariableSetterImpl wxMakeVarSetter(T& var, const U& value) +{ + return wxPrivate::VariableSetterImpl(var, value); +} + +// calling wxMakeVarSetter(ptr, NULL) doesn't work because U is deduced to be +// "int" and subsequent assignment of "U" to "T *" fails, so provide a special +// function for this special case +template +inline +wxPrivate::VariableNullerImpl wxMakeVarNuller(T& var) +{ + return wxPrivate::VariableNullerImpl(var); +} + +#endif // wxHAS_NAMESPACES + // ============================================================================ -// public stuff +// macros for declaring unnamed scoped guards (which can't be dismissed) // ============================================================================ -// wxScopeGuard is just a reference, see the explanation in CUJ article -typedef const wxScopeGuardImplBase& wxScopeGuard; - -// when an unnamed scope guard is needed, the macros below may be used -// // NB: the original code has a single (and much nicer) ON_BLOCK_EXIT macro // but this results in compiler warnings about unused variables and I // didn't find a way to work around this other than by having different -// macros with different names +// macros with different names or using a less natural syntax for passing +// the arguments (e.g. as Boost preprocessor sequences, which would mean +// having to write wxON_BLOCK_EXIT(fwrite, (buf)(size)(n)(fp)) instead of +// wxON_BLOCK_EXIT4(fwrite, buf, size, n, fp)). -#define wxGuardName wxMAKE_UNIQUE_NAME(scopeGuard) +#define wxGuardName wxMAKE_UNIQUE_NAME(wxScopeGuard) #define wxON_BLOCK_EXIT0_IMPL(n, f) \ wxScopeGuard n = wxMakeGuard(f); \ - wxPrivate::Use(n) + wxPrivateUse(n) #define wxON_BLOCK_EXIT0(f) \ wxON_BLOCK_EXIT0_IMPL(wxGuardName, f) #define wxON_BLOCK_EXIT_OBJ0_IMPL(n, o, m) \ wxScopeGuard n = wxMakeObjGuard(o, m); \ - wxPrivate::Use(n) + wxPrivateUse(n) #define wxON_BLOCK_EXIT_OBJ0(o, m) \ - wxON_BLOCK_EXIT_OBJ0_IMPL(wxGuardName, o, m) + wxON_BLOCK_EXIT_OBJ0_IMPL(wxGuardName, o, &m) + +#define wxON_BLOCK_EXIT_THIS0(m) \ + wxON_BLOCK_EXIT_OBJ0(*this, m) + #define wxON_BLOCK_EXIT1_IMPL(n, f, p1) \ wxScopeGuard n = wxMakeGuard(f, p1); \ - wxPrivate::Use(n) + wxPrivateUse(n) #define wxON_BLOCK_EXIT1(f, p1) \ wxON_BLOCK_EXIT1_IMPL(wxGuardName, f, p1) #define wxON_BLOCK_EXIT_OBJ1_IMPL(n, o, m, p1) \ wxScopeGuard n = wxMakeObjGuard(o, m, p1); \ - wxPrivate::Use(n) + wxPrivateUse(n) #define wxON_BLOCK_EXIT_OBJ1(o, m, p1) \ - wxON_BLOCK_EXIT_OBJ1_IMPL(wxGuardName, o, m, p1) + wxON_BLOCK_EXIT_OBJ1_IMPL(wxGuardName, o, &m, p1) + +#define wxON_BLOCK_EXIT_THIS1(m, p1) \ + wxON_BLOCK_EXIT_OBJ1(*this, m, p1) + #define wxON_BLOCK_EXIT2_IMPL(n, f, p1, p2) \ wxScopeGuard n = wxMakeGuard(f, p1, p2); \ - wxPrivate::Use(n) + wxPrivateUse(n) #define wxON_BLOCK_EXIT2(f, p1, p2) \ wxON_BLOCK_EXIT2_IMPL(wxGuardName, f, p1, p2) #define wxON_BLOCK_EXIT_OBJ2_IMPL(n, o, m, p1, p2) \ wxScopeGuard n = wxMakeObjGuard(o, m, p1, p2); \ - wxPrivate::Use(n) + wxPrivateUse(n) #define wxON_BLOCK_EXIT_OBJ2(o, m, p1, p2) \ - wxON_BLOCK_EXIT_OBJ2_IMPL(wxGuardName, o, m, p1, p2) + wxON_BLOCK_EXIT_OBJ2_IMPL(wxGuardName, o, &m, p1, p2) + +#define wxON_BLOCK_EXIT_THIS2(m, p1, p2) \ + wxON_BLOCK_EXIT_OBJ2(*this, m, p1, p2) + + +#define wxSetterName wxMAKE_UNIQUE_NAME(wxVarSetter) + +#define wxON_BLOCK_EXIT_SET_IMPL(n, var, value) \ + wxPrivate::VariableSetter n = wxMakeVarSetter(var, value); \ + wxPrivateUse(n) + +#define wxON_BLOCK_EXIT_SET(var, value) \ + wxON_BLOCK_EXIT_SET_IMPL(wxSetterName, var, value) + +#define wxON_BLOCK_EXIT_NULL_IMPL(n, var) \ + wxPrivate::VariableSetter n = wxMakeVarNuller(var); \ + wxPrivateUse(n) + +#define wxON_BLOCK_EXIT_NULL(ptr) \ + wxON_BLOCK_EXIT_NULL_IMPL(wxSetterName, ptr) #endif // _WX_SCOPEGUARD_H_